slippy drive train?

[2clepto]

my chain wont engage with the front chain ring when pedal force is applied. does anyone know if the culprit is the chain or could it be the front chain ring is worn, middle on a triple? cheers

 

[ColinJ]

Do you mean that you can't get the chain to go onto the ring, or it slips when you try pedalling?

 

[2clepto]

"it slips when you try pedalling?" it does this. yet it pedals ok on the stand when i cleaned and set it up, but when you pedal with your body weight applied to the pedals the chain slips and wont engage. cheers.

 

[ColinJ]

I suspect that the chain and/or chainring is/are badly worn. Actually, the chain might be slipping on the cassette at the back instead - it is sometimes hard to tell unless you are looking down on it when it slips.

If the drivetrain is too worn you might have to end up changing the chainring, the chain AND the cassette. Often a new chain will slip on an old ring or cassette. You might be lucky and get away with just changing the most worn part.

The last time this happened to me I ended up having to do all 3 because new and old parts did not mesh together properly.

 

[lpretro1]

Put up a pic of the offending ring

 

[Ajax Bay]

could it be the front chain ring is worn, middle on a triple

Are you saying that the chain 'slips' only when on the middle chain ring (ie but is OK on the small and large)? While you're at it, and in the spirit of @ColinJ 's comment, measure your chain (ie 20 links, say) carefully to see it's not stretched. Should be 254mm and no more than 256mm.

 

[2clepto]

i think its only the mid chain ring. mainly because ive just got the bike and was fixing it up and the first pedal across my room and it seemed the front chain rings were not engaging well. heres a few snapshots,

fortunately i had a spare chain ring so trying that before i remove the chain, which doesn't have a split link, so unsure how id measure the chain whilst on the bike? without getting up to the eyes lol.

 

[Apollonius]

What a classic example of "very worn", "averagely worn" and "hardly worn at all" on one bike. Textbook!

Does the front changer actually work? It looks as if it has been ridden entirely on the middle ring!

 

[ColinJ]

Ha ha - yes, that definitely looks like a 'middle ring bike'! I'm amazed that it worked as long as it did.

It looks like the rings are riveted together so they would have to be changed as a set. I'd be surprised if the chain and cassette don't need replacing too, given how worn the ring is. I would replace everything and start with a nice new drivetrain.

 

[e-rider]

middle ring is shagged - simple

 

[2clepto]

Ha ha - yes, that definitely looks like a 'middle ring bike'! I'm amazed that it worked as long as it did.

It looks like the rings are riveted together so they would have to be changed as a set. I'd be surprised if the chain and cassette don't need replacing too, given how worn the ring is. I would replace everything and start with a nice new drivetrain.

good tips thanks. ill photo the rest of the drive train let me know what you think. ive already got the new chain handy, im not too into purchasing a 7 speed freewheel new, so heres hoping thats ok.

thanks erider.

the front mech didnt shift when i got it last week. its the dirtiest bike ive cleaned up i think in terms of muck being hardened between the cogs on the rear block and in the front mech, brakes and wheels. and its been riden to death but i think theres alot left in there. altho the forks seem to have lost their adjust function and remain permanently in the spongy position.

its a large hybrid or xl ill measure it but its too large for my size, but im interested for a while in riding a larger hybrid, ive already got a slightly larger than my size racer and i like it alot, almost like a sporty range rover in terms of roadview lol, whereas this hybrid feels and hopefully rides not unlike a small horse.

its a merida crossway, good tyres, rusty spokes, bit rusty round the gills, has been recabled, needs a puncture fixed lol, im hoping itll be a great bike to ride, but i doubt it because they rarely are...just need to set up the front mech, fix puncture, adjust brake again. thanks for the advice much appreciated.

 

[Ajax Bay]

unsure how id measure the chain whilst on the bike?

I suggested: "measure your chain (ie 20 links, say)". Use a steel ruler (ideally) and measure the chain along the top when in slight tension. Some have siad that this is difficult to do accurately. Given the state of the chainwheels (and you won't be able to replace just the middle one as @ColinJ has said), the chain almost certainly needs replacing anyway, as will the cassette. A replacement crankset of this type is very inexpensive and if you keep what's on there you will get frustrated and maybe worse (slipping just when you put power on eg up hill or turning into a main road and need assured reliability). Or resolve to ride it only on the large and small chainwheels eg go up (with multi changes on both derailleurs, from 48/25 to 28/15.

 

[e-rider]

from the photo it looks like the chainrings are not replaceable on that chainset; it must be a cheapo - that means a whole new chainset unfortunately.

 

[2clepto]

yes, the bikes ready to ride for a test. got the new 2nd hand chainrings on, theyre about the same weight as the worn ones and the same count of teeth. riding across the room indicates the problem was the middle chain ring worn out and not the rear cassette or the chain. altho the chain needs one or two links removing to tighten it up but ill replace it once ive tested it for 15 mins outside 2mrw. best of all the bike cost £20 last week. size 58cm.

below is the two deterioration points on the bike.

any ideas? im just going to leave them and just ride the bike as is. the one on the rear stays where a rear brake caliper could be fitted, the paint around the hole has flaked off so i wrapped it in a little sticky metal tape to stop it from getting any worse. thanks for all your help this morning.